Method of securing together heavy steel plates.



J. H. GRAVELL.

METHOD O F SECURING TOGETHER HEAVY STEEL PLATES.

' APPLICATION FILED JULY 26. L918.

v Patented Mar. 11, 1919.

IN VEN A TI'ORNEYS UNITED STATES PATENT OFFICE.

. JAMES H. GBAVELII, OI BROOKLYN, N Ew YORK, ABSIGNOB TO THOMSON SPOT WELDER' COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

IETHOD, OI SECURING TOGETHER HEAVY STEEL PLATES.-

. Specification of Letters Patent. Patented Mar. 11, 1919.

i Application am July, 191:. lerhllo.248,826.

To all whom it may concern:

' welding Be it known that L James H. Gmvm, a citizen of the United States, and a resident of Brooklyn, in the county of Kings.

and State of New York,-have invented certain new and useful Improvements in Meth- Plates, of which the following is a specification.

This invention relates to uniting heavy plates of metal face to face by means of an auxiliary member such as a slug or rivet and utilizes the electric heating and welding process to effect this end. 4 A

The object of the invention is to secure a strong joint between heavy'plates or sheets in a u1ck and efiicient manner.

It is well known that spot welding is a very satisfactory process on relatively thin sheets of metal but when the sheets are of considerable thickness, for example around.

one half an inch thick and upward, the spot rocess becomes. unsatisfactory owing to t e enormous electric currents required and owing to inability to secure suit able electrodes which 'will retain the taper end under the enormous pressure necessary.

Heretofore it has been the custom to as-' semble heavy plates by means-of rivets, either fire heated or electrically heated. The rivetin has many objections however, the princi pal one being the necessity of registering the holes in the two plates through which the rivet blank must pass.

Thepresent invention resembles a combination of the riveting and s ot welding proc-. esses and it consists in the improved method of securing plates together face to face hereafter more particularly described and then.

specified in the claims.

In the accompanying drawin Figure 1 illustrates a cross section throug two heavy plates assembled for welding according to this invention.

Fig. 2 is a similar view showing a subsequent stage of the operation.

Fig. 8 1s a similar view showing the end of the operation. I

Fig. 4 is a diagrammatic view illustrating a slight modification in the recess.

Figs. 5 and 6 illustrate the operation.

Fig. 7 diagrammatically illustrates the final etc and shows a cross-section through the fini ed joint.

rther steps in;

'1 and 2 indicate two heavy plates of metal supe d on each other in surface contact.

The p ate-1 is provided with a perforation 3 plate 2. The outer end of the rivet blank may be provided initially with the usual head 6 or it may initially be merely a straight shank as shown in Fig. 4. u

The parts are assembled between current and pressure supplying blocks7 and 8. These blocks form the terminals of the secondary circuit of an electric transformer and pass current from one to the other through the interposed Work and also apply pressure thereto all as well understood to those skilled in the electric welding art.

Preferably the lower surface of the upper block 7 is flat .and engages the upper part of the rivet head 6 and'upon starting the flow of current it passes from the block 7 through the rivet blank 4, across the contact between the tapered end 5 and the plate 2 and through the plate 2 to the block 8. This flow of current causes the end of the rivet blank and that part of the plate 2 with which it contacts to become heated and softened and u on application of pressure by means of t e block 7 the parts are comrivet shank 4 but also through the plates 1 and 2 direct, its path being widened out as indicated by the dotted lines in Fig. 2. The head 6 at this time localizes the welding pressure and the flow of current in the meetmg surfaces of the plates 1 and 2 and the continuation thereof for the desired interval results inthe formation ofan efiective welding of the material of the meeting faces of the plates 1 and 2 to one another by a weld of an. area and form practicall conforming to the head 6. The current an ressure are preferably continued until the ead is emedded in the plate 1 at which time the plates and the rivet blank are united together by a homogeneous weld as indicated in Fig. 3.

Instead of initially providing the rivet blank with a head to act as a slug or button to transmit the current and pressure direct through both plates in the intermediate stage ofthe process, the rivet blank ma in the initial stage be a straight shank wit out a head as indicated in Fig. 4.

In this case the flow of current from one block to the other through the Work and the a plication of pressure causes the outer end of the rivet blank 4 to mushroom and form the head 6 as indicated in Fig. 5 and the current and pressure continuing, the head seats on the plate 1 and acts as in the previously described case to localize the current and pressure in the meeting surfaces of the plates and effect a welding thereof as previously described and as indicated in Fig. 7

It will be understood that my invention is not limited in any manner except as may b specified in the appended claims.

What I claim as my invention is:

1. The method of securing two members together, consisting in provlding a perforated member, passing a rivet blank through said member and into contact with the other member, electrically welding said blank to the second named member, continuing the current and pressure until the head of the rivet engages the perforated member and thereafter to cause the head to act as a' slug or button to Weld the three members to-.

gether.

2. The method of securing two members together, consisting in providlng a perforated member, passing a rivet blankv through said member and into: abutted contact with" a an im erforate surface of the other member,

electrlcally Welding said blankto the imperforate member, forcing the rivet head into contact with the perforated member and gether, consisting in passin the heating current and pressure throug the members in line with said head to cause the plates .to weld direct to each other.

3. The method of securin two members to provi ing one member with a perforation, superposmg the members, inserting a rivet blank through the perforation and into contact with an imperferate surface of the other member, electrically weldin said rivet to the imperforate member an continuing the current and pressure after the rivet head has become seated to cause the three members to weldtogether.

4. The method of uniting two plates, consisting inproviding a perforated and an imperforate plate, inserting a rivet blank through a perforation in one plate and abutted ,a must the other plate, electrically welding t e blank to the lmperforate plate and at the same time causing the outer end of the blank to mushroom over on the outer surface of the perforated plate and continuing the current and ressure to weld the plates direct to each ot er.

5. The method of uniting plates, consisting in superposing a perforated and an imperforated plate, inserting a rivet blank through the perforated plate and into abutted contact with the other plate, electrically welding the blank to the imperforate plate while at the same time causing the blank to mushroom and form a head on the outside of the'plate and thereafter continuing the current and ressure to cause the plates to bewelded direct to each other by means of said head.

i n York and State of New York, this 25th day of July A. D. 1918.

. JAMES H. GRAVELL.

Witnesses:

F. B. Townsnnn,

ed at New York,.in the'countyof New 

